“Mona Lisa effect“ is real, but doesn’t apply to Leonardo’s painting

Enlarge / Researchers at Bielefeld University in Germany used folding rulers for measurement to test the effect. Study participants indicated the number they thought Mona Lisa's gaze was directed at. (credit: CITEC/ Bielefeld University)

There have long been anecdotal reports that the eyes of the Mona Lisa—Renaissance artist Leonardo da Vinci's most famous painting—sometimes seem to follow viewers as they move around the artwork. The phenomenon is even called the "Mona Lisa effect" because of it. But a new study published in the journal i-Perception found that she's really "looking" to the right-hand side of her audience.

"There is no doubt about the existence of the Mona Lisa effect," the authors wrote. "It just does not occur with the Mona Lisa herself."

The study grew out of ongoing research at Bielefeld University in Germany on human communication with robots and avatars. Directional gaze is key when designing gaming avatars or virtual agents, for instance. That's one way an avatar/agent can indicate attention, perhaps directing a player/user towards objects that are relevant to the task at hand.